1. Field of the Invention
The present invention relates to an endoscope and an endoscopic system to which the endoscope is applied, and more particularly to an endoscope which includes an insertion portion having a distal end side opening of a treatment instrument insertion channel in a distal end portion, and which is employed for a desirable treatment with a use of a guide wire made to stick out from the distal end side opening and guided to an affected area, and an endoscopic system to which the endoscope is applied.
2. Description of the Related Art
In recent years, so called side-looking type endoscopes provided with an imaging optical system at a distal end portion of an insertion portion are employed for treatments of affected areas in alimentary tract system, pancreaticobiliary duct system, and the like. The side-looking type endoscope is employed for treatments such as a preparatory treatment, in which contrast agent is injected into a bile duct or a pancreatic duct before diagnosis, and a therapeutic treatment, in which a gallstone present in a common bile duct or the like is removed with a use of a balloon, a grasper, or the like.
When the treatment is performed on the pancreatic duct, bile duct, hepatic duct, or the like with the use of the endoscope, the distal end portion of the insertion portion of the endoscope is inserted into a duct to be treated such as the pancreatic duct, bile duct, hepatic duct, or the like. However, since the pancreatic duct, bile duct, hepatic duct, and the like are extremely thin ducts, the insertion of the distal end portion of the insertion portion of the endoscope is not easy. Therefore, a following procedure is generally taken.
First, the distal end portion of the insertion portion of the side-looking type endoscope is inserted into an area around a duodenal papilla. Then, while keeping the area under radioscopy, the operator guides the guide wire penetrating through the treatment instrument insertion channel and makes the guide wire stick out from an opening which opens in a lateral direction in the distal end portion of the insertion portion of the endoscope, and further inserts the guide wire into a desired duct to be treated such as the pancreatic duct, bile duct, hepatic duct, or the like. Thereafter, the operator inserts a treatment instrument such as a catheter into the desirable duct to be treated such as the pancreatic duct, bile duct, hepatic duct, or the like using the guide wire as a guide.
Here, the guide wire or the treatment instrument runs in an axial direction of the insertion portion of the endoscope. Therefore, the guide wire and the treatment instrument advance in the same direction. When one desires to insert the guide wire or the treatment instrument through the opening of the treatment instrument insertion channel in the distal end portion of the insertion portion and into a duct such as the pancreatic duct, bile duct, hepatic duct, or the like, he/she needs to change the direction of advance of the guide wire or the treatment instrument around the opening of the insertion portion. For this purpose, the side-looking type endoscope has a treatment instrument raiser in the distal end portion of the insertion portion. The operator can change the direction of advance of the guide wire or the treatment instrument which advances in the axial direction of the insertion portion to a radial direction by raising the treatment instrument raiser.
Thus, once the guide wire is inserted into the extremely thin duct such as the pancreatic duct, bile duct, hepatic duct, or the like, the operator can insert and withdraw various types of treatment instruments into and out of the duct using the guide wire as a guide.
When the treatment instrument is withdrawn from the pancreatic duct, bile duct, or hepatic duct, the guide wire is sometimes withdrawn together with the treatment instrument against the will of the operator due to close contact between the treatment instrument and the guide wire. Since the pancreatic duct, bile duct, or hepatic duct is an extremely thin duct, as described above, the insertion of the guide wire thereinto is difficult to perform. Therefore, it is extremely cumbersome and troublesome for the operator to reinsert the guide wire into the pancreatic duct, bile duct, hepatic duct or the like.
Hence, the operator needs to devise some ways to prevent the withdrawal of the guide wire on removing the treatment instrument from the pancreatic duct, bile duct, hepatic duct, or the like. For the above purpose, conventionally, after the operator moves the treatment instrument to a certain extent in a direction of withdrawal, an assistant of the operator pushes back the guide wire, which moves together with the treatment instrument, towards a direction of the pancreatic duct, bile duct, hepatic duct, or the like. Alternatively, the guide wire is held so as not to move and be withdrawn together with the treatment instrument, for example. Such an operation is extremely cumbersome and requires plural personnel, i.e., at least the operator and the assistant. As can be seen from the foregoing, the endoscopic diagnosis and treatment take long time for treatment due to the cumbersome operation, and places higher financial burden on both the hospital and the patient since its operation needs many personnel.
To solve the problems as described above, some propose an endoscope having a mechanism including a treatment instrument raiser which can secure the guide wire at a predetermined position when raised up. For example, see Japanese Patent Application Laid-Open No. 2002-34905 and Japanese Patent Application Laid-Open No. 2003-116777.
The endoscope described in Japanese Patent Application Laid-Open No. 2002-34905 has a slit for securing the guide wire on a top of a guiding surface of the treatment instrument raiser. When the treatment instrument raiser is raised, the guide wire is engaged with the slit of the treatment instrument raiser, thereby secured relative to the endoscope.
On the other hand, the endoscope described in Japanese Patent Application Laid-Open No. 2003-116777 has a guide wire engaging groove to secure the guide wire on a guiding surface of the treatment instrument raiser, and a guide wire securing mechanism near a forceps channel opening in an operation portion.
The endoscopes according to the documents mentioned above, secure the guide wire relative to the endoscope between the treatment instrument raiser and a predetermined portion of the distal end portion of the insertion portion of the endoscope while the treatment instrument is withdrawn. Thus, these endoscopes can prevent the withdrawal of the guide wire from the pancreatic duct, bile duct, hepatic duct, or the like at the time of removal of the treatment instrument.
However, the guide wire, which has an elongated shape though hard, is not always parallel with the axial direction of the endoscope at a position right out from the treatment instrument insertion channel. Therefore, the axial direction of the guide wire can take any direction on the guiding surface of the treatment instrument raiser.